Objectives To explore childhood maltreatment as a risk factor for mental-physical multimorbidity across disease areas and examine gender as a potential effect modifier.

Methods We analyzed data from the 2022 Mental Health and Access to Care Survey. We described sample characteristics with unweighted counts, survey-weighted percentages, and weighted chi-square tests. Missing data were addressed via multiple imputation. Entropy balancing adjusted for age, gender, LGBTQ2+ identity, visible minority group, and immigration status and multinomial logistic regression was used to estimate associations between the number of childhood maltreatment subtypes reported and physical (≥ 2 physical conditions but no mental), mental (≥ 2 mental conditions but no physical), and mental-physical (≥ 1 mental and physical condition) multimorbidity. Survey weights were applied during both entropy balancing and regression modeling. Effect modification by gender was examined and sub-analyses of mental-cardiometabolic, mental-inflammatory, and mental-somatic multimorbidity were conducted.

Results 8,967 respondents were included. Mental-physical multimorbidity increased with maltreatment exposure: 3.4% (none, n=4647), 6.3% (1 type, n=2804), 10.1% (2 types, n=1208), and 18.2% (3 types, n=308). Adjusted odds ratios for mental-physical multimorbidity ranged from 2.15 (95% CI:1.90-2.44) for 1 type to 8.72 (95% CI:7.01-10.85) for 3 types compared to physical (aOR=1.31-2.00) and mental (aOR=1.90-3.63) multimorbidity. Men showed higher odds of mental-physical multimorbidity at high exposure levels (aOR=6.14, 95% CI:4.90-7.70 in women; aOR=13.96, 95% CI:9.58-20.34 in men) with varying effect sizes across disease areas.

Conclusion Childhood maltreatment shows a strong dose-response association with mental-physical multimorbidity. Further research is needed to clarify biopsychosocial mechanisms and gender-specific pathways.

The authors have declared no competing interest.

This study did not receive any funding.

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This secondary data analysis used publicly available data from the Mental Health and Access to Care Survey (MHACS) Public Use Microdata File and did not require institutional ethics review.

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